scholarly journals Dynamic changes of canopy-scale mesophyll conductance to CO2 diffusion of sunflower as affected by CO2 concentration and abscisic acid

2010 ◽  
Vol 34 (1) ◽  
pp. 127-136 ◽  
Author(s):  
RUDI SCHÄUFELE ◽  
JIRI SANTRUCEK ◽  
HANS SCHNYDER
Keyword(s):  
Abscisic Acid ◽  
Co2 Concentration ◽  
Mesophyll Conductance ◽  
Dynamic Changes ◽  
Co2 Diffusion

scholarly journals The Light Dependence of Mesophyll Conductance and Relative Limitations on Photosynthesis in Evergreen Sclerophyllous Rhododendron Species

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1536
Author(s):  
Ying-Jie Yang ◽  
Hong Hu ◽  
Wei Huang
Keyword(s):  
Light Intensity ◽  
Negative Relationship ◽  
Light Response ◽  
Co2 Concentration ◽  
Limiting Factor ◽  
Mesophyll Conductance ◽  
Co2 Diffusion ◽  
Rate Limiting Step ◽  
Internal Cavities ◽  
Rate Limiting

Mesophyll conductance (gm) limits CO2 diffusion from sub-stomatal internal cavities to the sites of RuBP carboxylation. However, the response of gm to light intensity remains controversial. Furthermore, little is known about the light response of relative mesophyll conductance limitation (lm) and its effect on photosynthesis. In this study, we measured chlorophyll fluorescence and gas exchange in nine evergreen sclerophyllous Rhododendron species. gm was maintained stable across light intensities from 300 to 1500 μmol photons m−2 s−1 in all these species, indicating that gm did not respond to the change in illumination in them. With an increase in light intensity, lm gradually increased, making gm the major limiting factor for area-based photosynthesis (AN) under saturating light. A strong negative relationship between lm and AN was found at 300 μmol photons m−2 s−1 but disappeared at 1500 μmol photons m−2 s−1, suggesting an important role for lm in determining AN at sub-saturating light. Furthermore, the light-dependent increase in lm led to a decrease in chloroplast CO2 concentration (Cc), inducing the gradual increase of photorespiration. A higher lm under saturating light made AN more limited by RuBP carboxylation. These results indicate that the light response of lm plays significant roles in determining Cc, photorespiration, and the rate-limiting step of AN.

scholarly journals Mesophyll conductance to CO2 transport estimated by two independent methods: effect of variable CO2 concentration and abscisic acid

2009 ◽  
Vol 60 (8) ◽  
pp. 2315-2323 ◽  
Author(s):  
D. Vrábl ◽  
M. Vašková ◽  
M. Hronková ◽  
J. Flexas ◽  
J. Šantrůček
Keyword(s):  
Abscisic Acid ◽  
Co2 Concentration ◽  
Mesophyll Conductance ◽  
Co2 Transport

scholarly journals Mesophyll conductance in cotton bracts: anatomically determined internal CO2 diffusion constraints on photosynthesis

2018 ◽  
Author(s):  
Jimei Han ◽  
Zhangying Lei ◽  
Jaume Flexas ◽  
Yujie Zhang ◽  
Marc Carriquí ◽  
...  
Keyword(s):  
Mesophyll Conductance ◽  
Co2 Diffusion ◽  
Internal Co2 ◽  
Cotton Bracts

scholarly journals Three Methods of Estimating Mesophyll Conductance Agree Regarding its CO2 Sensitivity in the Rubisco-Limited Ci Range

Plants ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 62 ◽  
Author(s):  
James Bunce
Keyword(s):  
Co2 Concentration ◽  
C3 Plants ◽  
Oxygen Sensitivity ◽  
Mesophyll Conductance ◽  
Rubisco Activity ◽  
Limited Region ◽  
Co2 Sensitivity ◽  
Low Co2 ◽  
Co2 Concentrations ◽  
Data Points

Whether the mesophyll conductance to CO2 movement (gm) within leaves of C3 plants changes with CO2 concentration remains a matter of debate, particularly at low CO2 concentrations. We tested for changes in gm over the range of sub-stomatal CO2 concentrations (Ci) for which Rubisco activity limited photosynthesis (A) in three plant species grown under the same conditions. Mesophyll conductance was estimated by three independent methods: the oxygen sensitivity of photosynthesis, variable J fluorescence combined with gas exchange, and the curvature of the Rubisco-limited A vs. Ci curve. The latter assay used a new method of rapidly obtaining data points at approximately every 3 μmol mol−1 for Rubisco-limited A vs. Ci curves, allowing separate estimates of curvature over limited Ci ranges. In two species, soybean and sunflower, no change in gm with Ci was detected using any of the three methods of estimating gm. In common bean measured under the same conditions as the other species, all three methods indicated large decreases in gm with increasing Ci. Therefore, change in gm with Ci in the Rubsico-limited region of A vs. Ci curves depended on the species, but not on the method of estimating gm.

Effects of drought on photosynthesis in grapevines under field conditions: an evaluation of stomatal and mesophyll limitations

2002 ◽  
Vol 29 (4) ◽  
pp. 461 ◽  
Author(s):  
Jaume Flexas ◽  
Josefina Bota ◽  
José M. Escalona ◽  
Bartolomé Sampol ◽  
Hipólito Medrano
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport Rate ◽  
Net Photosynthesis ◽  
Co2 Concentration ◽  
Vitis Vinifera L ◽  
Severe Drought ◽  
Mesophyll Conductance ◽  
Progressive Decline ◽  
Effects Of Drought ◽  
Combined Measurements

The effect of diffusional and photochemical limitations to photosynthesis was assessed in field-grown water-stressed grapevines (Vitis vinifera L.) by combined measurements of gas exchange and chlorophyll fluorescence. Drought was slowly induced, and the progressive decline of photosynthesis was examined in different grapevine cultivars along a continuous gradient of maximum mid-morning values of stomatal conductance (g), which were used as an integrative indicator of the water-stress conditions endured by the leaves. Initial decreases of g were accompanied by decreases of substomatal CO2 concentration (Ci), the estimated chloroplastic CO2 concentration (Cc) and net photosynthesis (AN), while electron transport rate (ETR) remained unaffected. With increasing drought, g, AN, Ci and Cc further decreased, accompanied by slight decreases of ETR and of the estimated mesophyll conductance (gmes). Severe drought led to strong reductions of both g and gmes, as well as of ETR. The apparent carboxylation efficiency and the compensation point for CO2 remained unchanged under severe drought when analysed on a Cc, rather than a Ci, basis, suggesting that previously reported metabolic impairment was probably due to decreased gmes.

scholarly journals Abscisic Acid Induces Rapid Reductions in Mesophyll Conductance to Carbon Dioxide

PLoS ONE ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. e0148554 ◽  
Author(s):  
Giuseppe Sorrentino ◽  
Matthew Haworth ◽  
Said Wahbi ◽  
Tariq Mahmood ◽  
Shi Zuomin ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Abscisic Acid ◽  
Mesophyll Conductance

Stomatal Limitation of Photosynthesis in Abscisic Acid-Treated and in Water-Stressed Leaves Measured at Elevated CO2

1988 ◽  
Vol 15 (4) ◽  
pp. 495 ◽  
Author(s):  
SP Robinson ◽  
WJR Grant ◽  
BR Loveys
Keyword(s):  
Abscisic Acid ◽  
Stomatal Conductance ◽  
Quantum Yield ◽  
Oxygen Evolution ◽  
Stomatal Closure ◽  
Co2 Concentration ◽  
Assimilation Rate ◽  
High Co2 ◽  
Co2 Concentrations ◽  
Ambient Co2

Feeding 10-5M (�)-abscisic acid (ABA) via the petioles of detached leaves of apricot (Prunus armeniaca) or sunflower (Helianthus annuus) decreased stomatal conductance and assimilation rate but not the calculated intercellular CO2 concentration (Ci) suggesting non-stomatal as well as stomatal inhibition of photosynthesis. Evidence for non-stomatal inhibition was not observed in spinach (Spinacia oleracea). There was no significant decrease in rates of electron transport nor ribulosebisphosphate carboxylase (Rubisco) activity in intact chloroplasts isolated from ABA-treated sunflower leaves. Oxygen evolution by leaf discs with 3% CO2 in the gas phase was inhibited in ABA- treated sunflower and apricot leaves but not in spinach; the inhibition was only half as great as the inhibition of assimilation rate at ambient CO2. The quantum yield of oxygen evolution decreased in ABA-treated sunflower leaves in proportion to the decrease in the light-saturated rate. There was no significant difference in room temperature chlorophyll fluorescence of ABA-treated leaves compared to controls. Stomatal conductance of sunflower leaves decreased by more than 90% when the CO2 concentration was increased from 340 ppm to 1000 ppm but at much higher CO2 concentrations the stomata appeared to reopen. Stomatal conductance at 2-3% CO2 (20 000-30 000 ppm) was 50% that at ambient CO2. This reopening of stomata at high CO2 was inhibited in previously water-stressed or ABA-treated plants. In unstressed leaves, the maximum rate of oxygen evolution occurred at 0.5-2% CO2 but in ABA-treated leaves 10-15% CO2 was required for maximum rates. It is suggested that stomatal closure may limit photosynthesis in ABA-treated or previously water-stressed leaves even at the relatively high CO2 concentrations normally used in the leaf disc oxygen electrode. The inhibition of photosynthesis by ABA is largely overcome at saturating CO2. The apparent non-stomatal inhibition suggested by gas exchange measurements and the decreased quantum yield could be explained by patchy stomatal closure in response to ABA.

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